An Ultra-Efficient Modern Home in Sarasota, Fla.

Tuesday, Sep 23 2014
Posted by:
Nigel F. Maynard

Faced with a site adjacent to a wetland in need of reclamation, Josh Wynne Construction designed and built a high-performance, green home with a HERS index of minus 22.

“Power Haus is a beautiful home that compromises nothing while managing to shatter the ceilings perceived to exist in luxury green home building,” said the Sarasota, Fla.-based company.

The clients had a few requests: a home with a generous great room for entertaining guests and for enjoying the outdoor. “They like to entertain so they wanted an open house with views of that wetland,” Josh Wynne, president of the company, said.

Wynne Construction’s first order of business was fixing the land adjacent to the construction site, which had been overrun by invasive species. The builder improved the wetland and created a park-like setting, which is now full of deer, hogs, turkeys and ducks. “It’s pretty much like living on a wildlife preserve,” Wynne said.

The builder conceived the 3,000-plus-sq.-ft-home as a “modern cabin” — a single-width room that opens to the outdoor. Because the property is a working horse ranch, the clients wanted a home that fit the vernacular. But they also like modern architecture, so the builder referenced traditional Florida architecture.

“I looked to cracker architecture, dog trot designs and four square homes,” Wynne said. “We used passive cooling, passive lighting and passive ventilation techniques because part of the clients’ design program is that they wanted to have the house open as much of the year as possible and be comfortable.”

Because the house is not coastal and because it’s located on a swamp, it does not have the benefit of constant breeze. But it does have a predominant western winds during the more temperate months of the year—spring and fall—so they positioned the house with a western exposure facing a heavy hardwood tree line.

“During the sunny months when the sun dips past the eaves it also dips behind the trees, so the west is never fully exposed to the sun,” Wynne explained. “But in the cooler months, the trees drop their leaves so you get a nice warming effect,”

The building envelope is well insulated, made from masonry blocks to resist high wind loads. But the builder injected foam into the voids, created a 1½-in. airspace and used an R-7.1 secondary wall insulation.

“In Florida, we don’t have heat loss and heat gain horizontally,” Wynne said. “Unlike up north, all of our heat loss happens vertically here, so we went with an R-36 closed-cell foam roof insulation.” An Energy Star metal roof tops the whole thing.

The home features two master suites and two flex spaces. Wynne built the interiors to be durable and to control moisture, so walls are American Clay plaster and everything else — trim, ceilings — is cypress, an exterior-rated wood that is very durable. Floors are concrete and FSC-certified massandaruba inlay and the cabinets were fabricated from drops at a rough mill. “We picked up all the trash material from the curb and built panels for all the cabinetry,” the builder said.

At the time of certification, it was highest-rated new construction LEED Platinum house in the world, Wynne said, and received the outstanding building award from USGBC. With a HERS index of minus 22, the home had the lowest ever recorded by Energy Star and the DOE Builder’s Challenge (at the time), Wynne said.

“Power Haus was designed to exceed every standard in green construction while maintaining the clients’ desired aesthetic and comfort requirements,” the explained. “It is a shining example of the level of performance and sustainability that can be achieved while maintaining a high standard of quality, comfort and design.”

Photos: Matt McCourtney/McCourtney Photographics.